The invention relates to heat exchangers and in particular to air cooled heat exchangers or condensers. More particularly the invention relates to an improved inlet flow distribution arrangement positioned within the condenser inlet header to minimize maldistribution of the entering liquid-vapor mixture.
Air cooled heat exchangers usually include a plurality of heat exchange tubes arranged in rows one behind the other in the direction of airflow of the cooling air. Fluid enters the condenser inlet header, which communicates with the inlet ends of the tubes, and then flows through the tubes wherein it is condensed or cooled. Fans blow cooling air across the tubes in an airflow direction generally perpendicular to the rows of tubes. The fluid is cooled and/or condensed by the cooling air to form condensate as it travels through the tubes, and the condensate is collected at the outlet ends of the tubes in a suitable manner.
It has been found that a problem exists when the fluid entering the inlet header is a mixture of liquid and vapor. In such instances, the dense liquid tends to move towards the ends of inlet header, due to its inertia, causing the tubes in communication with such ends to receive a disproportionate amount of the liquid than the other tubes. This results in the flooding of the end tubes, which reduces the available heat transfer surface. Also, the subcooled liquid also increases the stresses in the tubes due to the temperature differential between the tubes containing a disproportionate amount of subcooled liquid and the tubes containing a disproportionate amount of the vapor. Further, flooding of the end tubes with subcooled liquid may result in freezing of the condensate within such tubes under certain operating conditions.